Railcar backup cooling system

Abstract

A railcar backup cooling system may be added to an existing railcar (e.g., a boxcar) to provide supplemental or backup cooling to the railcar in the event that an HVAC failure or other circumstance occurs, which causes the interior temperature of the railcar to rise. The system includes a container of liquid or compressed gas mounted on the railcar, a valve controlling the flow of the liquid or gas from the container, and a controller configured to open the valve when the HVAC system fails or is otherwise unable to maintain the railcar at the desired temperature. When the valve is opened, the liquid and/or gas stored in the container may exit, expanding into a cool gas and thereby acting to cool the railcar environment.

What is claimed is: 
     
       1. A system comprising:
 a railcar cooled using a primary heating, ventilation, and air conditioning (HVAC) system; 
 a tank positioned within the railcar, the tank configured to store a fluid under a first pressure and at a first temperature, the first pressure greater than atmospheric pressure; 
 a valve; 
 a controller configured to:
 receive, from the primary HVAC system, an alert message indicating that the primary HVAC system has failed; 
 in response to receiving the alert message, open the valve such that a portion of the fluid from the tank travels from the tank and through the valve; an expansion valve configured to reduce a pressure of the portion of the fluid from the valve such that the portion of the fluid expands into a gas having a second temperature lower than the first temperature; 
 
 a heat exchanger configured to transfer heat from air surrounding the heat exchanger to the gas from the expansion valve; and 
 a fan configured to circulate the air surrounding the heat exchanger. 
 
     
     
       2. The system of  claim 1 , wherein the valve is an electromagnetic valve. 
     
     
       3. The system of  claim 1 , further comprising a probe configured to measure a temperature in an interior of the railcar, wherein the controller is configured to open the valve in response to the measured temperature exceeding a threshold. 
     
     
       4. The system of  claim 1 , further comprising a switch configured to detect whether a door of the railcar is open, wherein the controller is configured to close the valve in response to the switch detecting that the door of the railcar is open. 
     
     
       5. The system of  claim 1 , wherein the heat exchanger is further configured to direct the gas to outside the railcar. 
     
     
       6. The system of  claim 1 , further comprising a pressure regulator configured to adjust a pressure of the portion of the fluid from the tank. 
     
     
       7. A method comprising:
 storing, by a tank positioned within a railcar that is cooled using a primary heating, ventilation, and air conditioning (HVAC) system, a fluid under a first pressure and at a first temperature, the first pressure greater than atmospheric pressure; 
 receiving, from the primary HVAC system, an alert message indicating that the primary HVAC system has failed; 
 in response to receiving the alert message, opening a valve such that a portion of the fluid stored in the tank travels from the tank and through the valve; reducing, by an expansion valve, a pressure of the portion of the fluid from the valve such that the portion of the fluid expands into a gas having a second temperature lower than the first temperature; 
 transferring, by a heat exchanger, heat from air surrounding the heat exchanger to the gas from the expansion valve; and 
 circulating, by a fan, the air surrounding the heat exchanger. 
 
     
     
       8. The method of  claim 7 , wherein the valve is an electromagnetic valve. 
     
     
       9. The method of  claim 7 , wherein the condition is a measured temperature in an interior of the railcar exceeding a threshold. 
     
     
       10. The method of  claim 7 , further comprising:
 detecting whether a door of the railcar is open; and 
 closing the valve in response to detecting that the door of the railcar is open. 
 
     
     
       11. The method of  claim 7 , further comprising directing, by the heat exchanger, the gas to outside the railcar. 
     
     
       12. The method of  claim 7 , further comprising adjusting, by a pressure regulator, a pressure of the portion of the fluid from the tank. 
     
     
       13. A system comprising:
 a railcar cooled using a primary heating, ventilation, and air conditioning (HVAC) system; 
 a tank positioned within the railcar, the tank configured to store a fluid under a first pressure and at a first temperature, the first pressure greater than atmospheric pressure; 
 a valve; 
 a controller configured to:
 receive, from the primary HVAC system, an alert message indicating that the primary HVAC system has failed; and 
 in response to receiving the alert message, open the valve such that a portion of the fluid from the tank travels from the tank and through the valve and such that the portion of the fluid expands into a gas having a second temperature lower than the first temperature; and 
 
 an atomizer configured to spray the gas into the railcar. 
 
     
     
       14. The system of  claim 13 , wherein the valve is an electromagnetic valve. 
     
     
       15. The system of  claim 13 , further comprising a probe configured to measure a temperature in an interior of the railcar, wherein the controller is configured to open the valve in response to the measured temperature exceeding a threshold. 
     
     
       16. The system of  claim 13 , further comprising a switch configured to detect whether a door of the railcar is open, wherein the controller is configured to close the valve in response to the switch detecting that the door of the railcar is open. 
     
     
       17. The system of  claim 13 , further comprising a pressure regulator configured to adjust a pressure of the portion of the fluid from the tank.